JP2018155092A - Method for removing contaminant on inner face of pipeline - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a removing (cleaning) time of a contaminant in a pipeline and to reduce a use amount of a pressure-fed fluid.SOLUTION: A method for removing a contaminant on an inner face of a pipeline comprises: putting a pig 20 from a part (a launcher L) of a pipeline A into the pipeline; pressure-feeding a fluid from the part of the pipeline into the pipeline, to move the pig 20 in the length direction of the pipeline; peeling a contaminant on an inner face of the pipeline by friction of the pig with the inner face of the pipeline; and taking out the pig and the peeled contaminant together with the fluid out of another part (a catcher C) of the pipeline. Multiple pigs 20 can be used in a manner that before a preceding pig reaches the another part of the pipeline, a following pig is moved from the part of the pipeline successively, independently and freely (feeding pigs successively). At this time, the following pig is made harder than the preceding pig, and/or a diameter of the following pig is made larger than that of the preceding pig. By feeding the pigs successively, cleaning time can be shortened and a use amount of the pressure-fed fluid can be reduced.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for removing impurities on the inner surface (inside) of a fluid pipe such as waterworks, agricultural water, and industrial water, and an apparatus used for the method.

  This type of pipeline, for example, water pipelines such as waterworks, agricultural water, industrial water, etc., after a long period of common use, deposits from water quality adhere to the inner surface (inside) or when water is taken In some cases, solid matter such as sand accumulated in the water deposits, the cross-sectional area of water (fluid) passing through may decrease, or the observation of the function diagnosis of the pipeline may be hindered. Hereinafter, the precipitates and solids are referred to as “contaminants”.

Pipes where such foreign substances are deposited and adhered become deficient due to poor flow of water and other fluids, making it impossible to flow the required flow rate, and turbid foreign substances from accumulated foreign substances. Runoff causes water quality deterioration. For this reason, conventionally, a method for removing impurities in the pipeline has been proposed. For example, a pig is introduced into a pipe line from a part (input port) of a pipe line, and a fluid (water) is pumped into the pipe line from a part of the pipe line so that the pig is placed in the length direction of the pipe line. A pipe that travels, removes the impurities in the pipe line by the friction between the pig and the inner surface of the pipe, and pushes it forward, and takes out the pig and the separated dirt from the other part (discharge port) together with the fluid. There is a method of removing impurities on the road inner surface (see Patent Documents 1 and 2).
The conventional method for removing contaminants on the inner surface of a pipeline is to prepare a plurality of pigs with different diameters, and gradually introduce the smaller diameter pigs into the pipeline in order from the smaller ones to gradually remove the contaminants. Like to do.

JP 2002-200465 A JP 2009-189910 A JP 2009-22918 A JP, 2006-107247, A Japanese Patent No. 6232650

In the prior art, each pig is introduced into the pipeline after the inserted pig is taken out (recovered) from the other part of the pipeline. This is to confirm whether the pig has completed the removal of the contaminants. At this time, if the pig does not reach the other part of the pipeline even if the required amount of pumping fluid is fed (if the pig is clogged in the pipeline), insert the boosting pig and push the forward pig out with that pig. (See Patent Document 1, paragraph 0021).
Repeating the pumping of the fluid every time it passes from one part of the pipe of one pig to another part (every passage) is a waste of fluid, and each time a pig is inserted, a device for that purpose is installed. It takes a lot of time to fix the problem, and the pause time (water shut-off time) of the pipeline that removes the contaminants becomes longer, which greatly affects the social life of the area where the pipeline is laid.

  This invention makes it a subject to reduce the usage-amount of a pumping fluid while shortening the removal time of a contaminant under the above actual condition.

In order to achieve the above object, according to the present invention, the forward pig is inserted and continuously run before the forward pig reaches the other part of the pipe. In other words, this contaminant removal method is referred to as the “continuous ball method”. In this continuous ball method, the normal cleaning method is to collect and collect one pig in one cleaning, and the pigs in the charging / recovering action are recovered. While repeating multiple times with different diameters, etc., throwing a plurality of balls one after the other with a predetermined interval (distance) in the pipeline and removing them by running independently independently It was.
When the forward pig is in the pipeline and the backward pig is put into the pipeline and pushed by the fluid, the forward pig is pushed through the fluid between the previous and next pigs to remove contaminants. It proceeds (runs) while performing and reaches the takeout part (other part). At this time, as shown in FIG. 1 of Patent Document 3, since each pig is allowed to travel freely in the pipeline without connecting the cleaning tool (pig), each pig is related to the trend of other pigs. Eliminates impurities and performs efficient removal. Moreover, even if the future pig remains in the pipeline due to some reason, it is pushed by the backward pig and reaches the take-out section together.
In this way, if the pigs are continuously inserted (according to the continuous ball method), impurities can be removed by each pig, compared with the case where the removal action is performed for each passage of each pig. The working time is shortened, and the amount of pig running fluid is also reduced. Moreover, since the insertion of a pig is a repetition of the same operation, if the same operation is repeated continuously, the installation time of the insertion device for the pig can be shortened, and the water shutoff time during washing can be greatly reduced.

As a specific configuration of the present invention, a pig is introduced into a pipe line from a part of the pipe line, and a fluid is pumped into the pipe line from a part of the pipe line so that the pig is inserted in the length direction of the pipe line. As the pig travels, the contaminants in the pipeline are peeled off and pushed forward by friction between the pig and the pipeline inner surface, and the pig and the separated contaminants are taken out from the other part of the pipeline. A method for removing contaminants, wherein the plurality of pigs are continuously run from the part to the forward pig before the forward pig reaches the other part of the pipeline, and the forward pig and the forward pig It is possible to adopt a configuration in which the pig is allowed to travel independently and freely.
At this time, the “joint ball method” includes a mode in which there are two or more pigs in the pipe, and naturally includes a mode in which all the pigs are located in the pipe. However, a mode in which the pig is clogged in the pipe line and the pig for boosting is introduced is not included. The method of throwing a pig into the pipe line by the continuous ball method is to throw one pig into the pipe line, stop it halfway, and repeat the action of throwing the next pig, or continuously with multiple throwers. (See FIG. 12).
Traveling in the pipe line of the pig is not performed by a means for pumping fluid from a part of the pipe line into the pipe line. The flow allows the pig to run (the pig can be run by the fluid originally present in the conduit).

  In this configuration, the hardness of the above-mentioned pig may be harder in the backward pig than the forward pig, or the diameter of the backward pig may be larger than the diameter of the forward pig, or both may be adopted. it can. On the other hand, the hardness of the above-mentioned pig is made softer in the rear pig than in the future pig, the diameter of the rear pig is made smaller than the diameter of the forward pig, or both are adopted. You can also. The hardness and diameter, and the order of inserting the different pigs are appropriately set based on experiments and actual operations so that the cleaning effect can be improved and the time can be shortened based on the condition of the pipe line.

Usually, if the hardness of a pig becomes high, the peeling effect will increase in the case of the same diameter. If the water permeability is high, there is an effect that it is easy to move by loosening the impurities in front of the pig traveling direction by running water passing through the pig. For this reason, it is preferable to first add a pig with high water permeability and gradually add a pig with a high elastic constant even if the water permeability is low.
In any case, it is preferable that the forward pig and the backward pig have different densities, water permeability, and elastic constants (elastic coefficients). The ratio of the pipe inner diameter and the pig diameter is preferably 1: 1.0 to 1.5. Furthermore, it is preferable to change the hardness of the pig according to the material of the pipe line.
Thus, the impurities can be smoothly removed by gradually increasing the hardness of the pig to be added (hardening), gradually increasing the diameter, or the like. The hardness here refers to the hardness when measured with an Asker rubber hardness meter C type. Its hardness affects the elastic constant.
Differentiating the density, water permeability, and elastic constant of the above pigs effectively exhibits a function based on the different pigs because each pig runs independently and freely.

  In addition, if the traveling of the pig in the pipe line is performed by fluid inflow from the pig feeding section, for example, it has a plurality of feeding machines and a fluid pressure pump, and each feeding machine is connected via a switching valve. If the configuration is adopted in which each input device is individually and selectively connected to the pipeline and the pump by the switching valve, the entire device can be reduced in size. As described in Japanese Patent Application Laid-Open No. 2004-228620, the pig can be run in the pipeline by inflow of fluid from the conduit.

  As described above, according to the present invention, the forward pig and the forward pig are continuously run by inserting the backward pig before the forward pig reaches the other part (extraction part) of the pipeline. Since it is allowed to run independently and independently, it is possible to shorten the time for removing contaminants and to reduce the amount of pumping fluid, thereby improving work efficiency and reducing work costs. .

BRIEF DESCRIPTION OF THE DRAWINGS It is an experimental pipeline figure for implementing the contaminant removal method in the pipeline which concerns on this invention, (a) is a schematic diagram, (b) is an enlarged view of a branch part. Examples of pigs (PC balls) used in one embodiment of the same contaminant removal method Illustration of measurement of water permeability of pig Illustration of measurement of pig's elastic constant A schematic diagram of continuous ball cleaning is shown, (a) when there is no contaminant in the pipeline, (b) when the contaminant is interposed Sectional drawing of the pipe line of one Embodiment of the same foreign material removal method Illustration of measuring the frictional force of a pig Pig density measurement result explanatory diagram Pig elastic constant measurement result explanatory diagram Illustration of other permeability test of pig Pigment permeability measurement result explanatory diagram Main part pipeline diagram of other embodiments

The experimental pipeline shown in FIG. 1 was manufactured, and in this pipeline A, the effect of removing impurities in the pipeline was tested. The pipe is made of pipe material, and the pipe 1 is made of transparent vinyl chloride (nominal diameter: φ100, outer diameter: 114 mm, inner diameter: 104 mm, thickness: 5 mm) so that the inside can be observed, and a launcher (input) Machine) In addition to L and catcher (receiver) C, branch sections (branches 1 to 4) were installed at intervals of about 20 m.
A pressure gauge (analog 4a and digital 4b) is installed in the launcher L and the catcher C to monitor the pressure and collect data, and a flow meter 5 is installed in the catcher C to set the flow velocity in the pipe. went. The pipe length and the like are as shown in Table 1 below. In the figure, 6 is a pump and 7 is a water tank.

The launcher L and the catcher C are conventionally well-known ones disclosed in Patent Document 4 and the like, and a pig 20 described later can be put into the pipe and can be taken out from the pipe.
As shown in FIG. 1B, the branch portion (branch 1 to 4) 10 has a T-shaped tube 11 interposed between the pipes 1, and a single tube 12 is connected to the mouth of the single tube 12. The upper end is closed by a flange or lid, and by removing the lid, the pig 20 is inserted, removed, the cleaning distance is changed, or the discharge port of the pig 20 in the event that the pipe line is blocked And so on.

  The pig 20 has a spherical shape made of a soft urethane resin foam as shown in FIG. 2, and is shown in Table 2 as soft type 20Y (FIG. 2 (a), No. 1-5 in Table 1), hard type. 20B (the figure (b), No. 6-10 of the table), hollow type 20C (the figure (c), No 11-12 of the table), molded product type 20W (the figure (d), No 13 of the table) Was made. Hereinafter, the generic symbol of these pigs 20Y, 20B, 20C, and 20W is “20”.

The soft type 20Y and the hard type 20B are solid (solid) open cells, and the hollow type 20C is obtained by dividing the hard type 20B in two and cutting it out (forming the hollow 21) to form a molded product. Type 20W was mold forming, and the other 20Y and 20B (C) were cut and shaped into a spherical shape after foaming. The numbers following Y, B, C, and W in the “Nominal Diameter” column in Table 2 indicate “Nominal Diameter”, for example, “Y-110” indicates “Soft Type 20Y and Nominal Diameter: 110”.
In this experiment, the soft type 20Y was colored yellow, the molded product type 20W was colored white, and the hard type 20B and the hollow type 20C were colored black. Moreover, the hardness measured with the Asker rubber hardness tester C type of the soft type 20Y was 2 to 5, and the hardness of the hard type 20B was 10 to 20.

Table 3 shows the results of obtaining the density from the normal temperature volume and the dry mass for the soft type Y-110 and the hard type B-110. The numerical value shows the average value of two measurements each, and the normal temperature means the temperature when the experimental place is not air conditioned, and the dry mass is also not the air conditioned of the experimental place. The mass before the experiment in the atmosphere. In this experiment, the temperature was 15 ° C. and the humidity was 60%.
From this result, the soft type Y-110 has an apparent density of about 0.05 (g / cm ³ ), and the hard type B-110 has a level of about 0.08 (g / cm ³ ).

Furthermore, water permeability was calculated | required about soft type Y-110 and hard type B-110, and the result is shown in Table 4. As shown in FIG. 3, the water permeability is fitted into a φ104 transparent VP (vinyl chloride) pipe (pipe 1) so that the water w does not pass through between the two, and the pig 20 passes through as indicated by an arrow. Water permeability (cm / s) = permeated water volume (cm ³ ) / (passage cross-sectional area (cm ² ) × passage time (s)).

Further, the elastic constants were obtained for the soft type Y-110 and the hard type B-110, and the results are shown in Table 5. As shown in FIG. 4, the elastic constant is obtained by placing a pig 20 on an upper pan balance H, applying a load N through a plate, and the diameters from the natural state are 70% (w ₇₀ ) and 50% (w ₅₀ ), the load (N) necessary for compression was determined. At this time, the load when the compression diameter d from the natural state is 70% is “w ₇₀ ”, the load when the compression diameter d is 50% is the increment “w ₅₀ −w ₇₀ ” from the 70% time point, and its elastic constant (N / cm) was obtained by = load (N) / section displacement (cm). The section displacement was the distance between the natural diameter and 70% compression diameter when the compression rate was 30%, and the distance between the natural diameter and 50% compression diameter when the compression rate was 50%. In Table 5, the left column of “compression diameter d” indicates “ratio of compression diameter to natural diameter%”, and the right column indicates “compression diameter”.

  “Pipe inner diameter ratio” when each of the pigs 20 is put into the pipe A, “pushing pressure (water pressure)” into the launcher L, and “starting pressure” for moving the pig 20 into the pipe A Table 6 shows “steady pressure (water pressure from start to discharge)” and “discharge pressure”.

According to this experimental result, when the pig (PC ball) 20 is solid, there is almost no difference due to the difference in hardness, but the influence of the diameter is remarkable (Nos. 1, 2 and 3 to 5), The ratio rises rapidly from around φ150 where the ratio to the inner diameter of the tube exceeds 1.5 (No 3 to 5, No 8 to 10). On the other hand, the hollow pressure (No. 11, 12) does not increase so much even if it is φ150.
The starting pressure and the steady pressure are substantially constant at 0.01 to 0.03 MPa except that the starting pressure tends to increase when the hard type is φ150 or more (No. 8 to 10).
The discharge pressure tended to be the highest in a series of pressure fluctuations. When the discharge pressure was 0.3 MPa or more, vibration and stagnation of the pipe line due to water hammer pressure were felt.

Next, in the above-mentioned pipeline A, in the no-load state (without the pig 20), the same pump pressure: 0.3 MPa, discharge rate: 19.8 m ³ / h (flow rate: 0.7 m / s) Table 7 shows the movement time and movement speed of each section (start position S (launcher L) → branch 1, etc.) of each pig 20 below. In addition, the discharge pressure and flow rate of the pump were determined from the actual values of cleaning work in the waterworks.

According to this experimental result, under the same pressure and the same flow rate, the speed difference between the soft type 20Y (No. 1 to 5) and the hard type 20B (No. 6 to 10) is significant. The speed of the type 20B is about 80 to 85% of the soft type 20Y.
For the hollow type 20C (No11, 12), φ120 (No11) has an intermediate value between the soft type 20Y and the hard type 20B, and φ150 (No12) is equivalent to the hard type 20B.

Further, the operation of the pump 6 is set in the same manner as in the experiment of Table 7 above, and the forward pig 20 is continuously run before the forward pig 20 reaches the other part (catcher C) of the pipe A, Table 8 and FIG. 5 (a) show the results of an experiment in which the forward pig 20 and the backward pig 20 run independently and simultaneously at the same time ("ball game" experiment).
In each experiment No. 1 to 6 in this table, the order and type of the pigs 20 introduced, the positions of the pigs 20 at the time of launching (injection) and arrival (distance from the launcher L), and the distance between them are shown in FIG. A schematic diagram thereof is shown in a). In FIG. 5A, the gray round pig is the soft type 20Y, and the black round pig is the hard type 20B. The same applies to FIG. 5B below.
At this time, after throwing the first throw from the launcher L, the pig 20 actuated the pump 6 to stop it by a predetermined distance, and thereafter throws the second and subsequent throws in the same procedure. When the planned number of pigs 20 has been introduced (with all pigs 20 located in line A, preferably up to branch 1 or up to branch 2), pump 6 is reactivated. The pigs 20 were moved all at once, and when the first throw arrived at the elbow immediately below the catcher C, the pigs 20 were stopped (water injection stopped). The measurement items are the position of the pig 20 immediately after the insertion, the interval between the second and subsequent throws, the movement distance when the pig 20 of the first throw reaches the elbow immediately below the catcher C, the interval between the second and subsequent throws, And travel time.

  From this experimental result, if the hardness is the same (Experiment Nos. 1 to 3), the ratio of the relative positions of the plurality of pigs 20 changing during the movement of 80 m is within 15%, and the distance decreases. On the other hand, when the soft type 20Y and the hard type 20B are sent together (Experiment No. 4 to 6), the hard type 20B tends to be delayed, and the hard type 20B is 85 to 90 from the travel distance of the soft type 20Y and the hard type 20B. % Speed difference, which is consistent with the basic experiment trend in Table 7 above.

Next, the pig 20 was allowed to pass through the continuous ball method in the state where the contaminants a and a ′ were present in the pipe A, and the cleaning performance and the behavior of the pig 20 were confirmed. At this time, as shown in FIG. 6, the input amount of the foreign substances is assumed that the foreign substances a and a ′ are accumulated 1/4 of the inner diameter of the pipe A (pipe 1) and 100 m in length. The mass was calculated by multiplying the specific gravity or density of sand a and silt mixed clay a ′. In addition, the specific gravity of the sand (sand sand No. 5) a is 1.56, and the on-site collected soil (silted clay) a ′ has a density of 2.81 (g / cm ^{3) based on} the analysis result of the same kind of soil conducted in the past. ), A mass per unit volume of 1.41 (kg / cm ³ ) with a water content ratio of 120% was used.
As for the input type and order of the pig 20, the first throw: Y-120 → second throw: B-150 in the order from the experience in the water supply and the results of applied experiments, and the third throw for the on-site sampling soil a ′ Y-180 was added. That is, the diameter and hardness of the pig 20 to be put into the pipe line were sequentially increased and hardened. The results are shown in Table 9 and FIG. 5B, where the former is the experiment No1 and the latter is the experiment No2.

Sand a stopped when the first pig 20Y advanced about 1 m from the launcher L. For this reason, when the pressure is increased from 0.3 MPa to 0.4 MPa, the stagnated first pig 20Y gradually starts to move, and the action of pushing the upper part of the sand a on which the water flow passing through the pig 20Y has accumulated increases. The speed was increased and the sand a was pushed, and finally it was carried to the catcher C. However, the residue at the bottom of the tube could be confirmed with only the first throw, and it was confirmed that they were removed at the second throw (Pig 20B).
It was confirmed from the state during the cleaning by the continuous ball method that the second and third throws (only on-site sampled soil a ′) transported and removed the residue remaining after the first throw. . In this experiment No. 2, soft type 20Y was used for the third throw. From this, depending on the situation of the pipeline A, the soft type 20Y and the hard type 20B can be appropriately selected and thrown in the pig 20 having different hardness and diameter, or finally, the soft type 20Y can be finished and washed. It can be estimated that smooth impurities a and a ′ can be removed.

The following considerations were made from the above experimental results.
1. Confirmation of basic behavior of basic experiment (Pig (PC ball) 20) “Confirmation of pushing pressure, starting pressure, steady pressure and discharge pressure of catcher C of launcher L”
The reason why the pushing pressure of the launcher L is affected by the diameter of the pig 20 is that, in the launcher L, it is necessary to reduce the diameter of the uncompressed pig 20 to the inner diameter of the pipe A (pipe 1). In the types 20Y and 20B, it is a natural result that the pressing pressure corresponding to the diameter of the pipe A (pipe 1) is required. In addition, the hollow type 20C has been tried to enable large-diameter pipe cleaning from a small-diameter inlet, and it has been confirmed that the indentation pressure and discharge pressure can be kept lower than the solid types 20Y and 20B. However, on the other hand, the effect on detergency due to the decrease in repulsive force is considered to require separate verification, but the detergency will decrease.
The starting pressure and the steady pressure were almost the same for all types, and the starting pressure was only slightly increased with the hard type 20B having φ150 or more. This also shows that the hardness of the pig 20B appears as a repulsive force based on the elastic constant, and it is significant that the tendency can be grasped numerically.
With regard to the discharge pressure, it seems that water hammer pressure is generated because the pipe A is temporarily closed while the moving pig 20 passes through a smaller diameter than the pipe A (pipe 1). .
When the diameter and length of the pipe A are increased, the action may be increased, and it is considered that the management of the discharge pressure is an important factor.

2. Confirmation of moving speed under the same pressure When different types of pigs 20 are sent under practical conditions such as pump pressure: 0.3 MPa and pipe flow velocity: 0.7 m / s, the effect of the diameter of the pig It turns out that the influence of hardness comes out rather than. The soft type 20Y moves at a speed substantially equal to the flow speed at no load, while the hard type 20B has a speed of about 85 to 90%.

  As a reference, Table 10 shows the results of measuring the contact area, static friction force, and dynamic friction force in a φ104 transparent VP (vinyl chloride) pipe (pipe 1) for the pig 20 used this time. The measuring method is based on the method of FIG. At this time, the static frictional force N was read when the load F was applied only to the pig 20 and the value of the balance D at the moment when it started to move, and the dynamic frictional force N was about 30 mm / s. L is the contact length of the pig 20.

  From this experimental result, it was found that the dynamic friction force of φ150 hard type 20B is about twice that of soft type 20Y. Moreover, although the cause of the speed reduction of the hard type 20B is considered to be probably due to a difference in dynamic friction force, a difference in water permeability due to a difference in manufacturing method may be considered in part.

For the behavior in the continuous ball method,
Attention was paid to the positional relationship between each of the pigs 20Y and 20B during the movement to the catcher C from the state in which the first throwing pig was about 20 m ahead. That is, as for the change of the mutual interval during the movement of about 80 to 85 m, if the hardness is the same, the interval tends to be reduced, but the shortening margin is about 10 to 15% of the original interval.
When the hard type 20B is added to this, it moves with a delay of about 15% compared to the soft type 20Y, and when the soft type 20Y is finally inserted behind the hard type 20B, the interval is shortened by about 25-30% of the initial distance. Must be considered.
From this, it can be seen that it is preferable to insert the software type 20Y → the hardware type 20B in order (see FIG. 5A).

In the foreign matter removal experiment (sand and soil collected on site)
As shown in FIG. 6, the amount of foreign substances introduced into the pipeline was 300 kg for both sand (sand sand No. 5) a and on-site collected soil (silted clay) a ′. As for sand a, the pump pressure could be increased to 0.4 MPa and discharged, but the discharge time was 16 minutes, which was 5 times longer than the state without impurities. In view of the influence of pressure on the pipe A and the ideal condition of the inner surface of the simulated pipe, operation at 0.3 MPa or less is considered as a practical limit condition.
On the other hand, with respect to the on-site collected soil a ′, it was possible to discharge the entire amount at a pump pressure of 0.3 MPa, and it was confirmed that the second and third shots were transported while collecting the foreign matter left unloaded.
As for the detergency, it was predicted that the clay a ′ mixed with silt having tackiness at first was worse, but it was better than the sand a. This is because the inner surface of the simulated pipeline is good and there are many fine particles and the apparent specific gravity is light, and there are many floating particles that are not compacted soon after filling. I think that is also affecting.
From this experimental result, it can be said that the detergency deteriorates in the order of “clay mixed silt a ′” → “sand a” → “stone”.
Regarding the effect of the “ream ball method”, the state in which impurities a and a ′ were introduced (No. 3 time in Table 8: 4 minutes 22 seconds) and the state in which no impurities were present (No. 1 time in Table 8: 3 minutes 24) Compared with the case where the ball (pig) is individually passed three times, the amount of water and the time can be shortened.
From the results of this experiment, comparing the time and water amount between the continuous ball method and the three-time washing, it becomes as shown in Table 11 and it can be understood that the continuous ball method is superior.

  Furthermore, in order to verify whether the density, elastic constant (elastic modulus, elastic modulus), and water permeability of the PC ball (pig) 20 can withstand use, the PC ball 20 of each diameter is shown in FIG. Using a solid soft type and a hard type made of a soft urethane resin foam shown in (b), “density”, “water permeability”, and “elastic constant” were measured by the following methods.

"Density measurement"
For each PC balls 20, in the same manner as above, using Jitsusoto径(diameter) d volume obtained from (mm) (cm ³⁾ calculation results of the mass m (g), the following equation (1), the density ρ (G / cm ³ ) was calculated.
ρ = m / V (1)
The results are shown in Table 12 and FIG.
According to FIG. 8 and Table 12, the soft type is about 0.059 [g / cm ³ ], 0.058 [g / cm ³ ], and the hard type is 0.099 [g / cm ³ ], 0.091 [ g / cm ³ ], and the latter has a density as high as about 1.6 times that of the former.

"Elastic constant"
In FIG. 4, a flat weight scale is adopted instead of the upper pan scale H, and the pig 20 is placed on the upper surface (mounting surface) of the weight scale in the same manner as the measurement of the elastic constant, and the load is loaded through the plate. Multiplying N, the load (N) required to compress the natural diameter to 70% (w ₇₀ ) and 50% (w ₅₀ ) was determined.
The measurement results are shown in Table 13 and FIG. In Table 13, the left column of “compression diameter d” indicates “ratio of compression diameter to natural diameter%”, and the right column indicates “compression diameter”.
According to Table 13 and FIG. 9, it can be seen that the hard type elastic constant (elastic coefficient) is 1.2 to 1.5 times higher than the soft type and is hard.

"Water permeability"
The measurement was performed by the apparatus shown in FIG. The apparatus fixes a rubber ring 32 to both end faces of a 100 mm diameter vinyl chloride pipe 31 and addresses a rubber plate 33. The rubber plate 33 and the push ring 34 are connected with bolts and nuts 35 with the rubber ring 32 in between. By tightening, the inside of the pipe 31 is stopped. A 75 mm diameter vinyl chloride tube 37 closed with a wire mesh 36 is provided coaxially in the tube 31, and the PC ball 20 is loaded into the tube 31. Water W can flow into one of the pipes 31 via hoses 38, 38 provided with a plurality of valves 38a, 38b, 38c, and from the other of the pipes 31 via a hose 38 provided with a valve 38d. Thus, the water W can flow into the poly tank 39. In the figure, 38e is a water pressure gauge.

In this water permeability test apparatus, first, the leftmost valve 38a and the valve 38b on the straight line in the figure are opened to fill the pipe 31 with water. Next, the valve 38d on the outlet side (right side) is opened, and the air in the pipe 31 and the PC ball 20 is extracted and then the leftmost valve 38a is temporarily closed, and the hose 38 on the outlet side is placed in the poly tank 39. Put in.
In this state, the leftmost valve 38a is opened and the elapsed time from the opening time is measured by the stopwatch, and when 10 L of water enters the poly tank 39, the valve 38a and the stopwatch are stopped.
After this action, the lid 40 was opened, the size and type of the ball 20 were changed, and the above action was repeated to measure the water permeability of each PC ball 20. The measurement results are shown in Table 14 and FIG.

According to the result of this water permeability test, as shown in FIG. 11, it can be seen that the hard type ball 20B has a higher water permeability than the soft type ball 20Y. For this reason, it can be understood that the soft-type ball 20Y is more susceptible to water pressure than the hard-type ball 20B, which is preferable for the first removal of contaminants. That is, it can be seen that it is preferable to first remove impurities with the soft-type ball 20Y, and then remove the remaining impurities with the hard-type ball 20B.
Moreover, since the force which pushes the ball | bowl 20 will change if a water permeability changes, it can be said that the advancing speed in the pipe | tube 31 is easy to change. When the PC ball 20 is larger than the tube 31, the wrinkles that can be formed on the ball are increased, and the water permeability is likely to be affected.

From the above experiment, it can be confirmed that the cleaning by the continuous ball method is excellent, and thereby, it can be confirmed that the existing pipe line can be cleaned smoothly. The removal of contaminants in the pipe line may be performed before performing the function diagnosis of the pipe line, or after the removal, in addition to the removal of the contaminants in the conventional manner.
Needless to say, the cleaning by the continuous ball method can be applied not only to waterworks but also to other fluid pipelines such as agricultural pipelines (agricultural water pipelines) and chemical lines in chemical factories.
In addition, when throwing a plurality of pigs 20 into a pipe line continuously by the continuous ball method, it is preferable to prepare a plurality of launchers L. For example, in the embodiment shown in FIG. 12, both the launchers L and L are connected alternately (individually and selectively) to the pipeline A and the pump 6 by the circuit switching valve 8 and the pig 20 is inserted.
The pig 20 is not limited to a spherical shape, and may be a bullet shape described in Patent Document 1, FIGS. Moreover, it is preferable to coat the outer peripheral surface of the pig 20 with silicone rubber or the like that increases inertia.

In the above embodiment, since the pipe line is made of vinyl chloride, the soft type 20Y (yellow) → hard type 29B (black) → soft type 20Y (yellow) was introduced in this order, but depending on the material of the pipe Of course, in the case of a ductile cast iron pipe with an inner surface mortar lining, the soft type 20Y (yellow) → the soft type 20Y (yellow) → the hard type 29B (black) is charged in this order.
Thus, it should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

C Catcher L Launcher 1 Pipe 4 Pressure gauge 5 Flow meter 20, 20Y, 20B, 20W Pig (PC ball)

Claims (5)

Pig (20) is introduced into the pipe (A) from a part of the pipe (A), and fluid is pumped into the pipe (A) from a part of the pipe (A), or the pipe The pig (20) is caused to travel in the length direction of the pipe (A) by the fluid originally present in (A), and the pig (20) and the pipe (A) are moved along with the running of the pig (20). The impurities (a, a ′) in the pipe (A) are peeled off and pushed forward by friction with the inner surface, and the pig (20) and the peeled impurities (a, a ′) from the other part of the pipe (A). ) To remove contaminants on the inner surface of the pipeline,
The plurality of pigs (20Y, 20B, 20W) are continuously run with the forward pigs from the part to the pipe (A) before the forward pig reaches the other part of the pipe. And a contaminant removal method on the inner surface of the pipeline, wherein the forward pig and the backward pig are allowed to travel independently and freely.   The method for removing contaminants on the inner surface of the pipe according to claim 1, wherein the hardness of the pig (20) is harder in the backward pig (20) than in the forward pig (20). The method for removing contaminants on the inner surface of the pipe according to claim 1 or 2, wherein the diameter of the pig (20) is larger in the backward pig (20) than in the forward pig (20).   The pipe according to any one of claims 1 to 3, wherein the running of the pig in the pipe (A) is performed by a fluid inflow from a pig inlet or a fluid originally present in the pipe (A). A method for removing impurities on the road surface. A pipeline cleaning device used in the contaminant removal method on the inner surface of any one of claims 1 to 4,
A plurality of charging machines (L) and a fluid pressure pump (6) are provided, and each of the charging machines (L) is connected to the pipe (A) and the pump (6) via a switching valve (8). Each connected to
A line cleaning device characterized in that the input devices (L) are individually and selectively connected to the line (A) and the pump (6) by the switching valve (8).

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